Apparently the question "Who is going to shoot Obama" received a laugh from those in attendance. And like mke_bt said, Republican Rep. Paul Broun did not condemn the question of assassination, but responded with the following:

The thing is, I know there’s a lot of frustration with this president. We’re going to have an election next year. Hopefully, we’ll elect somebody that’s going to be a conservative, limited-government president that will take a smaller, who will sign a bill to repeal and replace Obamacare.

"I deeply regret that this incident happened at all. Furthermore, I condemn all statements - made in sincerity or jest - that threaten or suggest the use of violence against the President of the United States or any other public official. Such rhetoric cannot and will not be tolerated."